Even before motorized vehicles were invented, it has been desirable to mount spring elements on the axles of carriages and the like to improve the ride, both to give passenger comfort and to reduce stresses on the vehicle suspension to prevent damage or reduce wear during operation. In motorized vehicles, particular concern has been given to the method of mounting suspension like components such as leaf springs to the drive or power axle of the car, truck or other vehicle.
To improve traction, control and performance, devices such as traction bars, ladder bars or four link rear suspensions are added to the vehicle. For example traction bars are designed to be rigid and push the vehicle from a point nearer the center of the vehicle allowing greater lift to the front end of the vehicle which improves traction and performance. The leverage from the drive axle is designed to be transmitted to the traction bars. These traction devices also stabilize the rear of the vehicle during acceleration and stopping thus increasing control of the vehicle.
Many existing devices are available that connect the axle housing and leaf spring of motorized vehicles. For example U.S. Pat. No. 4,061,364 entitled LEAF SPRING SUSPENSION SYSTEM issued to Robert R. Parks discloses a relatively standard suspension that has parallel threaded U-bolts 22 surrounding rear axle 16 and which extend towards leaf spring 28. Plate 20 is positioned on top of leaf spring 28 with the ends of U-bolts extending through holes in the corners of plate 20. Plate 20 is securely held to leaf spring 28 by bolts 24 which in turn secures leaf spring 28 to axle 16. Since U-bolts 22 are fixedly attached to axle 16, this prevents rotational movement of axle 16 relative to leaf spring 28.
U.S. Pat. No. 3,434,734 entitled AUXILIARY SPRING, issued to Gus L. Poulos, discloses another standard design that retains the central portion of leaf spring 20 between spring pads 21 and 22 fixedly attached to axle assembly 24 below frame 10 of the vehicle and is clamped by U-bolts 26 and a pressure plate 28 on top of leaf spring 20. Again, spring pads 21 and 22 prevent rotational movement of axle assembly 24 relative to leaf spring 20.
Similarly, U.S. Pat. No. 2,788,224 entitled SPRING SUSPENSION FOR LOAD-BEARING ROAD VEHICLES, issued to Michael Ramun et al., discloses a spring suspension device connecting load-bearing axle 18 and springs 11 and 12 whereby axle 18 is fixedly attached to the spring suspension device by split fittings 15. Split fittings 15 prevent rotational movement of axle 18 relative to springs 11 and 12.
There are several other patents of interest that disclose various devices connecting leaf springs to axle housings such as U.S. Pat. Nos. 5,119,543, issued to Bruce J. Reilly and 4,633,564, issued to Charles J. Sauber. Both of these patents also disclose a mounting preventing rotational movement of the axle housing relative to the leaf springs.
U.S. Pat. No. 3,257,123 entitled SPRING SUSPENSION FOR A VEHICLE, issued to Joe. L. Giovinazzo, discloses a fixed mount of a leaf spring 25/coil spring 22 combination with U-bolts 29. Although Giovinazzo discloses the use of nylon inserts 32 to prevent squeaking, it does not teach or suggest a moveable mount for an axle housing relative to the overall mount and a leaf spring.
It is noted that these previous devices do not allow for the free rotation of the axle housing relative to the leaf spring. Thus, at least some of the power and leverage from the drive axle is not transmitted to the drive wheels via traction bars, ladder bars, etc., as desired, but instead is transmitted to the leaf spring. This power and leverage loss decreases the efficiency of the drive system by not allowing the transfer of all the drive axle's power. Additionally, these traction devices with a rigid axle housing mount may allow spring wrap-up which causes wheel hop, lost traction and decreased control of the vehicle, sometimes with disastrous results.
In one instance it has been proposed to provide a floating housing mount for use with leaf spring suspensions when combined with ladder bars. The design, manufactured by Competition Engineering, employs two rollers in a floating housing mount. In this device, the entire rear end housing spins freely within its mounting. However the Competition Engineering Design requires multiple parts and requires great precision and high cost in the assembly of the rollers in the housing mount before it is mounted to the leaf spring and axle housing.
A roller assembly is not completely efficient in transmitting power and leverage from the drive axle to ladder bars, etc. The housing for the axle housing of the Competition Engineering Design is split and is connected by bolts and washers for assembly to the axle housing. As can be appreciated, such a construction weakens the design as compared to a one piece or welded design. Further, the roller assembly of the Competition Engineering Design does not present a smooth cylindrical surface so that any misalignment will cause wear and eventual failure as the bolts engage the rotatable axle housing. Of course, as soon as the vehicle is driven, misalignment begins as stresses on the rollers causes deformation or other adverse reactions with the axle housing.
Further, the nut and bolt assembly of the Competition Engineering Design does not present a planar side surface. Thus, when planar surface stops that are placed on the axle housing to prevent lateral movement of the Competition Engineering Design, uneven pressure is exerted on the Competition Engineering Design when it engages the stops. This can cause misalignment or cocking of the Competition Engineering Design and thus the leaf spring in relation to the axle housing, reducing the effectiveness in transmitting the power and leverage from the axle to the traction devices and the vehicle in general.
Accordingly, it is an object of the present invention to provide a leaf spring suspension that allows for free rotation of the axle housing relative to the leaf spring without the use of parts that are required to move during operation of the mount.
Another object of this invention is to provide a device which allows transmission of substantially all the power and leverage of a drive axle to traction bars, ladder bars, etc., to increase traction, control and performance of a vehicle.
Yet another object of the present invention is to provide a device capable of preventing spring wrap-up and wheel hop, and the resultant loss of traction and control of a vehicle.
Still another object of the present invention is to provide a device having a minimum of moving parts while allowing free rotation of the axle housing relative to the leaf spring.
Another object of the present invention is to provide a full floating axle rotating cap device of a sturdy design reducing its maintenance and repair costs.
A further object of the present invention is to provide a full floating axle rotating cap device that presents relatively planar side surfaces proximate the axle housing and to include stops on the axle housing to limit or prevent axial movement of the full floating axle rotating cap device on the axle housing.
Other objects will appear hereinafter.